It is always suggested you should opt for long term trading because it involves less risk as compared to short term trade. Short term trade can be compared to Day trade which is very risky as you never know when market will crash as I believe once in two weeks market is always red and such conditions can decrease your investment greatly.
I choose long-term trading for one reason - the lack of time. As soon as I have the job (from Monday to Friday), I cannot deal with the day trading. Everything is simple.